Self adjusting fifth wheel hitch

ABSTRACT

A fifth wheel hitch includes a locking member that engages surfaces of a pair of jaws to retain the jaws in a closed position. A release handle is operably connected to the locking member whereby movement of the release handle shifts the locking member out of engagement with the jaws to permit movement of the jaws to an open position. A ratchet type mechanism retains the locking member in an engaged position relative to the jaws and compensates for wear of the components and/or differences in size between kingpins.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. provisional patentapplication No. 61/605,998 filed on Mar. 2, 2012, entitled “SELFADJUSTING FIFTH WHEEL HITCH,” the entire contents of which isincorporated by reference.

BACKGROUND OF THE INVENTION

Various types of fifth wheel hitches have been developed to releasablycouple a king pin to a fifth wheel hitch. Over time, the components offifth wheel hitches tend to wear. Such wear may result in a looseconnection between the kingpin and the hitch.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a plan view of a fifth wheel hitch according to one aspect ofthe present invention;

FIG. 2 is a partially fragmentary, enlarged view of a portion of thehitch of FIG. 1 showing the jaws in an open position;

FIG. 3 is a plan view of the hitch of FIG. 1 showing the hitch is in aready to couple position;

FIG. 4 is a partially fragmentary isometric view of a portion of thehitch of FIG. 1; and

FIG. 5 is a partially fragmentary isometric view of a portion of thehitch of FIG. 1.

DETAIL DESCRIPTION OF THE PREFERRED EMBODIMENT

For purposes of description herein, the terms “upper,” “lower,” “right,”“left,” “rear,” “front,” “vertical,” “horizontal,” and derivativesthereof shall relate to the invention as oriented in FIG. 1. However, itis to be understood that the invention may assume various alternativeorientations and step sequences, except where expressly specified to thecontrary. It is also to be understood that the specific devices andprocesses illustrated in the attached drawings and described in thefollowing specification are simply exemplary embodiments of theinventive concepts defined in the appended claims. Hence, specificdimensions and other physical characteristics relating to theembodiments disclosed herein are not to be considered as limiting,unless the claims expressly state otherwise.

With reference to FIG. 1, a fifth wheel hitch 1 includes first andsecond jaws 2 and 3 that are pivotally mounted to a primary structure orhitch plate 25 via first and second pivot pins 4 and 5, respectively.Hitch plate 25 includes an outer peripheral surface 20 and a throat 27region defined by tapered side surfaces 27A and 27B. A first lockinglobe 8 is formed on first jaw 2, and a second locking lobe 9 is formedon second jaw 3 (see also FIG. 2). When the jaws 2 and 3 are in theclosed position illustrated in FIG. 1, a locking wedge 6 is received inan open area 7 formed between first and second locking lobes 8 and 9,respectively. Locking wedge 6 includes an elongated portion 13 that isslidably received in an opening 15 in a sidewall 16 of primary structure25. Body portion 17 of locking wedge 6 is slidably received in anopening 18 in a reinforcing rib structure 19 of primary structure 25.When hitch 1 is in the closed position the jaws 2 and 3 together form acircular or cylindrical opening 10 that receives a kingpin 11 of atrailer, and the locking wedge 6 contacts the locking lobes 8 and 9 toprevent rotation of the jaws 2 and 3 about pins 4 and 5, respectively.As discussed in more detail below, to release hitch 1, locking wedge 6can be moved forward in the direction of arrow “B” (FIGS. 2 and 3),thereby permitting rotation of jaws 2 and 3 about pins 4 and 5,respectively, in the direction of the arrows “A” (FIG. 1). Thus, thelocking wedge 6 selectively locks the jaws 2 and 3 in the closedposition of FIG. 1 to prevent inadvertent disconnecting of a fifth wheeltrailer from the hitch 1.

With further reference to FIG. 3, to release hitch 1, a user pullshandle 21, thereby moving the handle 21 in the direction of the arrow“F1”. A spring 12 generates a force “F2” tending to resist movement ofhandle 21 in the direction of the arrow “F1”. Handle 21 includes a plate22 with elongated slots 23 that receive pins 24 connected to primarystructure 25 to thereby guide the handle 21 as it moves due to forces F1and F2. As the handle 21 moves in the direction of the arrow F1, aroller/pin 26 attached to locking wedge 6 engages a side edge 27 of anangled slot 28 in plate 22, thereby shifting the locking wedge 6 in thedirection of the arrow “B.” This shifts the locking wedge 6 out ofengagement with locking lobes 8 and 9 of jaws 2 and 3, respectively.When the handle 21 is pulled to a fully extended position, roller/pin 26engages notch 29 at end 30 of angled slot 28 due to bias generated by aspring 14 (FIG. 1) biasing locking wedge 6 in a direction opposite thearrow B (see also FIG. 4). Notch 19 retains the locking wedge 6 in thedisengaged position illustrated in FIG. 3 after handle 21 is pulledoutwardly to release hitch 1.

After the handle 21 is moved to the fully extended position illustratedin FIG. 3, the kingpin 11 can be removed from between jaws 2 and 3. Asthe kingpin 11 is moved out, it pushes against the jaws 2 and 3, therebyrotating the jaws in the direction of the arrows A (FIG. 1) to the openposition illustrated in FIG. 3. As the jaws 2 and 3 rotate open, camsurfaces 32 and 33 on locking lobes 8 and 9, respectively (FIG. 2) pushagainst corner surfaces 38 and 39 of locking wedge 6, thereby shiftingthe locking wedge 6 in the direction of the arrow B. This movement oflocking wedge 6 disengages roller/pin 16 from notch 19 of angled slot18. Spring 12 generates a force F2 (FIG. 3) tending to pull handle 21into the retracted position. However, contact between surfaces 32 and 33of locking lobes 8 and 9, respectively, against corner surfaces 38 and39 of locking wedge 6 prevents movement of handle 21 to the fullyretracted position. Torsion springs 40 and 41 (FIG. 2) act on the jaws 2and 3, and hold the jaws 2 and 3 open after the kingpin 11 is removed.The torsion springs 40 and 41 do not, however, generate sufficient forceto open jaws 2 and 3 by themselves; the kingpin 11 opens jaws 2 and 3 asthe trailer is moved away from the hitch 1.

To recouple the trailer, the kingpin 11 is brought into contact with theinner surfaces 32 and 34 (FIG. 2), respectively of jaws 2 and 3, therebycausing the jaws 2 and 3 to rotate to the closed position illustrated inFIG. 1. As the jaws 2 and 3 rotate to the closed position, the lockingwedge 6 begins to slide into an engaged position between the lockinglobes 8 and 9 due to the bias of spring 14 biasing locking wedge 6 tothe engaged position. As the locking wedge 6 moves towards the jaws 2and 3, roller/pin 26 engages a series of steps 35 (FIG. 4) in angledslot 28. The steps 35 and roller/pin 26 together form a ratchet typemechanism and retain the locking wedge 6 and prevent the locking wedge 6from disengaging from the open/locking area 7 between locking lobes 8and 9 of jaws 2 and 3. Once the locking wedge 6 is in the fully engagedposition (FIG. 1), roller/pin 26 engages one of the steps 35, therebypreventing the locking wedge 6 from shifting out of engagement withlocking lobes 8 and 9.

As the components of the fifth wheel hitch 1 begin to wear, the lockingwedge 6 will tend to move further into the locking area 7 between thelocking lobes 8 and 9. However, the fifth wheel hitch 1 provides forautomatic seating of the lock wedge 6 in the correct position. As thecomponents wear, the wedge 6 automatically moves further as required,and the roller/pin 16 engages a step 35 (FIG. 4) in angled slot 28 toretain the locking wedge 6 in a tightly engaged position in contact withlocking lobes 8 and 9.

The fifth wheel hitch 1 of the present invention automatically couplesto either a new kingpin or a worn kingpin due to the self-adjustingfeatures of the hitch 1 discussed above. Thus, the hitch 1 can be usedwith different trailers having kingpins of different sizes withoutrequiring manual adjustment by the user.

The invention claimed is:
 1. A hitch assembly for releasably coupling toa kingpin of a trailer, the hitch assembly comprising: a hitch platestructure defining a forward portion and a rear portion having a throatwith tapered sidewalls; first and second jaw members rotatably mountedto the hitch plate structure for movement between an open positionwherein distal portions of the first and second jaws are spaced apart topermit a kingpin to be received between the distal portions of the firstand second jaws, and a closed position wherein the distal portions ofthe first and second jaws are proximate one another to form akingpin-receiving space; and wherein the first and second jaws definelocking surfaces that generally face one another and define alock-receiving space therebetween; a locking member movably mounted tothe hitch plate structure for movement in a first direction from adisengaged position permitting positioning of the first and second jawmembers in the open position, towards a plurality of engaged positionsin which a portion of the locking member is positioned between thelocking surfaces of the first and second jaws when the first and secondjaws are in the closed position, and wherein the locking member preventsrotation of the first and second jaws from the closed position to theopen position when the locking member is in an engaged position, andwherein the locking member is biased towards the engaged positions; arelease member operably connected to the locking member such thatmovement of the release member moves the locking member from any of theplurality of engaged positions to the disengaged position to permitrotation of the first and second jaws from the closed position to theopen position whereby a kingpin can be moved between the distal portionsof the first and second jaws; and: a releasable ratchet mechanism havingengaged and released configurations and permitting movement of thelocking member in the first direction when the releasable ratchetmechanism is in the engaged configuration, and substantially preventingmovement of the locking member in a second direction that is oppositethe first direction when the releasable ratchet mechanism is in theengaged configuration such that the releasable ratchet mechanism retainsthe locking member in a selected one of the plurality of engagedpositions.
 2. The hitch assembly of claim 1, wherein: the ratchetmechanism comprises an engagement member that engages a plurality ofnotches disposed on the release member, and wherein the engagementmember engages a selected one of the notches when the locking member isin a corresponding one of the engaged positions.
 3. The hitch assemblyof claim 2, wherein: the release member is movably mounted to the hitchplate structure for substantially linear motion in a third directionthat is transverse to the first direction; the release member includesan elongated slot defining inwardly-facing first and second opposedsurfaces, wherein the elongated slot extends at an acute angle relativeto the third direction; and wherein: the notches of the ratchetmechanism are formed on the first opposed surface of the slot.
 4. Thehitch assembly of claim 3, wherein: the inwardly-facing first and secondopposed surfaces are generally parallel to one another.
 5. The hitchassembly of claim 3, wherein: the release member comprises a plate, andwherein the slot is formed in the plate.
 6. The hitch assembly of claim3, wherein: the engagement member is disposed in the slot, and the slotincludes first and second opposite ends, and includes a retaining notchin the second opposed surface at the second opposite end, and whereinthe engagement member engages the retaining notch to thereby retain thelocking member in the disengaged position.
 7. The hitch assembly ofclaim 6, wherein: the engagement member comprises a pin extending fromthe locking member.
 8. The hitch assembly of claim 3, wherein: movementof the release member in the third direction tends to cause theengagement member to disengage from the notches.
 9. The hitch assemblyof claim 8, wherein: the release member is biased for movement in adirection opposite the third direction.
 10. The hitch assembly of claim1, wherein: the first and second jaw members include cam lobes formingthe locking surfaces.
 11. The hitch assembly of claim 10, wherein: thefirst and second jaw members pivot about first and second axes,respectively, and wherein the distal portions of the first and secondjaw members are disposed opposite the cam lobes such that the cam lobesmove towards one another as the distal portions of the first and secondjaws move away from one another as the first and second jaws rotate in afirst direction, and vice-versa.
 12. The hitch assembly of claim 1,wherein: the locking member includes a tapered end portion that engagesthe locking surfaces of the first and second jaw members when thelocking member is in an engaged position.
 13. A hitch assembly forreleasably coupling to a kingpin of a trailer, the hitch assemblycomprising: a kingpin having a generally cylindrical outer surfacedefining a diameter; a hitch plate structure defining a forward portionand a rear portion having a throat with tapered sidewalls; first andsecond jaw members rotatably mounted to the hitch plate structure formovement between an open position wherein distal portions of the firstand second jaws are spaced apart to define a gap that is at least aboutas large as the diameter of the kingpin to permit the kingpin to bereceived between the distal portions of the first and second jaws, and aclosed position wherein the first and second jaws form akingpin-receiving space and prevent movement of the kingpin from thekingpin-receiving space; and wherein the first and second jaws definelocking surfaces that generally face one another and define alock-receiving space therebetween; a locking member movably mounted tothe hitch plate structure for movement in a first direction from adisengaged position permitting positioning of the first and second jawmembers in the open position, and a plurality of engaged positionswherein a portion of the locking member is positioned between thelocking surfaces of the first and second jaws when the first and secondjaws are in the closed position, and wherein the locking member preventsrotation of the first and second jaws from the closed position to theopen position when the locking member is in one of the engagedpositions, and wherein the locking member is biased towards theplurality of engaged positions; a release member operably connected tothe locking member such that movement of the release member moves thelocking member from the engaged positions to the disengaged position topermit rotation of the first and second jaws from the closed position tothe open position whereby the kingpin can be moved out of thekingpin-receiving space; and: a releasable ratchet mechanism havingengaged and released configurations and permitting movement of thelocking member in a first direction when the releasable ratchetmechanism is in the engaged configuration, and substantially preventingmovement of the locking member in a second direction that is oppositethe first direction when the releasable ratchet mechanism is in theengaged configuration such that the ratchet mechanism retains thelocking member in a selected one of the plurality of engaged positions.14. The hitch assembly of claim 13, wherein: the ratchet mechanismcomprises an engagement member plurality of notches disposed on therelease member, and wherein the engagement member engages a selected oneof the notches when the locking member is in a corresponding one of theengaged positions.
 15. The hitch assembly of claim 14, wherein: therelease member is movably mounted to the hitch plate structure forsubstantially linear motion in a third direction that is transverse tothe first direction; the release member includes an elongated slotdefining inwardly-facing first and second opposed surfaces, wherein theelongated slot extends at an acute angle relative to the thirddirection; and wherein: the notches of the ratchet mechanism are formedon the first opposed surface of the slot.
 16. The hitch assembly ofclaim 15, wherein: the inwardly-facing first and second opposed surfacesare generally parallel to one another.
 17. The hitch assembly of claim15, wherein: the release member comprises a plate, and wherein the slotis formed in the plate.
 18. The hitch assembly of claim 15, wherein: theengagement member is disposed in the slot, and the slot includes firstand second opposite ends, and includes a retaining notch in the secondopposed surface at the second opposite end, and wherein the engagementmember engages the retaining notch to thereby retain the locking memberin the disengaged position.